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MySQL Articles
Page 295 of 355
Bulk change all entries for a particular field in MySQL?
Let us first create a demo table −mysql> create table BulkChangeDemo -> ( -> CustomerId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> CustomerName varchar(20), -> isEducated boolean -> ); Query OK, 0 rows affected (1.47 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into BulkChangeDemo(CustomerName, isEducated) values('Larry', true); Query OK, 1 row affected (0.09 sec) mysql> insert into BulkChangeDemo(CustomerName, isEducated) values('John', false); Query OK, 1 row affected (0.16 sec) mysql> insert into BulkChangeDemo(CustomerName, isEducated) values('Carol', false); Query OK, 1 row affected (0.25 sec) mysql> insert into BulkChangeDemo(CustomerName, ...
Read MoreMySQL index on column of int type?
Adding an index on column of int type is a good choice to run your query faster whenever your table has lots of records.If your table has less records then it is not a good choice to use index on column of int type.To understand the concept, let us create a table. The query to create a table is as follows −mysql> create table indexOnIntColumnDemo -> ( -> UserId int, -> UserName varchar(20), -> UserAge int, -> INDEX(UserId) -> ); Query OK, 0 rows affected (0.85 sec)Now check the description of table −mysql> desc ...
Read MoreMySQL find/ replace string in fields?
To find/replace string in fields, the syntax is as follows −update yourTableName set yourColumnName =REPLACE(yourColumnName, yourOldValue, yourNewValue);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table FindReplaceDemo -> ( -> FileId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> FileDirectory text -> ); Query OK, 0 rows affected (0.92 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into FindReplaceDemo(FileDirectory) values('C://User//MySQL'); Query OK, 1 row affected (0.19 sec) mysql> insert into FindReplaceDemo(FileDirectory) values('D://WebsiteImage//image1.jpg'); Query OK, ...
Read MoreMySQL select accumulated (running sum) column?
To select accumulated column, let us first create a demo table. The query to create a table is as follows −mysql> create table accumulatedDemo -> ( -> Value int -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into accumulatedDemo values(10); Query OK, 1 row affected (0.21 sec) mysql> insert into accumulatedDemo values(15); Query OK, 1 row affected (0.09 sec) mysql> insert into accumulatedDemo values(20); Query OK, 1 row affected (0.13 sec) mysql> insert into accumulatedDemo values(25); Query OK, 1 row affected ...
Read MoreCheck replication type in MySQL?
To check replication type, you can use SHOW GLOBAL VARIABLES command. The syntax is as follows −SHOW GLOBAL VARIABLES LIKE 'binlog_format';The above syntax returns either ROW, MIXED or STATEMENT. The default resultant is ROW.Now you can implement the above syntax to check replication type. The query is as follows −mysql> SHOW GLOBAL VARIABLES LIKE 'binlog_format';Here is the output −+---------------+-------+ | Variable_name | Value | +---------------+-------+ | binlog_format | ROW | +---------------+-------+ 1 row in set (0.10 sec)Here is the query to switch from ROW to STATEMENT −mysql> SET GLOBAL binlog_format = 'STATEMENT'; Query OK, 0 rows affected (0.04 ...
Read MoreDeclare syntax error in MySQL Workbench?
The DECLARE syntax must between BEGIN and END. The syntax is as follows −BEGIN DECLARE yourVariableName1 dataType, DECLARE yourVariableName2 dataType, . . . . ENDHere is the query to avoid DECLARE syntax error in MySQL −mysql> DELIMITER // mysql> create procedure declare_Demo() -> BEGIN -> DECLARE Name varchar(100); -> SET Name: ='John'; -> SELECT Name; -> END -> // Query OK, 0 rows affected (0.17 sec) mysql> DELIMITER ;Call the stored procedure with the help of CALL command. The syntax is as follows −CALL yourStoredProcedureName();The query is as follows −mysql> call declare_Demo();The following is ...
Read MoreWhat does a "set+0" in a MySQL statement do?
The set+0 converts the set value to integer. Let us see an example by creating a table −mysql> create table SetZeroDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> TechnicalSkills set('C', 'Spring Framework /Hibernate', 'Python', 'Django Framework', 'Core Java') NOT NULL -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into SetZeroDemo(TechnicalSkills) -> values('C, Spring Framework /Hibernate, Python, Django Framework, Core Java'); Query OK, 1 row affected (0.20 sec)Display all records from the table using select statement. The ...
Read MoreReserving MySQL auto-incremented IDs?
To reserve MySQL auto-incremented IDs, the syntax is as follows −START TRANSACTION; insert into yourTableName values(), (), (), (); ROLLBACK; SELECT LAST_INSERT_ID() INTO @anyVariableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table reservingAutoIncrementDemo -> ( -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY -> ); Query OK, 0 rows affected (0.45 sec)Insert some records in the table using insert command. The query is as follows −mysql> START TRANSACTION; Query OK, 0 rows affected (0.00 sec) mysql> insert into reservingAutoIncrementDemo values(), (), (), (); Query ...
Read MoreGet the number of days between current date and date field?
To get the number of days between current date and date field, the syntax is as follows −SELECT DATEDIFF(CURDATE(), STR_TO_DATE(yourColumnName, '%d-%m-%Y')) AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table DateDifferenceDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ArrivalDate varchar(100) -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into DateDifferenceDemo(ArrivalDate) values('12-10-2011'); Query OK, 1 row affected (0.14 sec) mysql> insert ...
Read MoreIgnoring the year in MySQL Query with date range?
To ignore the year with date range, use the DATE_FORMAT() with the between clause. Let us first create a demo table. The query to create a table is as follows −mysql> create table igonreYearDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ShippingDate date -> ); Query OK, 0 rows affected (0.75 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into igonreYearDemo(ShippingDate) values('2016-01-31'); Query OK, 1 row affected (0.16 sec) mysql> insert into igonreYearDemo(ShippingDate) values('2018-01-31'); Query OK, 1 row affected (0.13 sec) mysql> insert into ...
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